Mobile terminals now have access to increasingly abundant applications along with the rapid development of mobile communication technology. In the application development process of the iOS, the cache is used for storage of a variety of application data to serve the purpose of high-speed data access.
Currently, iOS platform employing the NSCache (a class, the iOS introduces for convenient caching of some objects) memory cache mechanism, however, there is no strict limit on the memory size of the cached data. That is, only after new cached data is stored such that the total amount of the currently stored cached data exceeds the memory limit, the iOS platform will delete the last stored cached data that overflows from the limit. With such storage strategy, the total memory size of the cached data may be likely to overrun the system memory limit after new cached data is stored, resulting in low storage speed and efficiency.